Sustainable Food for Cities? It’s a numbers game, not community food growing game

We’re facing urgent challenges with regard to sustainable food supplies, the stuff people were talking about at the Warwick Climate Forum earlier in the month.

The Sustainable Food Cities Conference I went to in Bristol last week was a stark contrast to the Warwick gathering. What underpinned much of the Bristol meeting about sustainable food supplies for cities were community food growing, passion and inspiration.

Don’t think for a nanosecond I don’t think urban food growing a Good Thing. It is. And for all sorts of reasons, some of which I’ve outlined before (see see How self-sufficient can Birmingham be? Should we even bother trying?). But fruit and veg patches, community orchards, even the odd flirt with hens or a few sheep on an urban farm has diddley-squat to do with providing a city population with a healthy diet, indeed even supplying food for a single family reliably and completely.

It’s widespread, this view that all we have to do is persuade communities to grow their own fruit and veg, experiment with acquaponics, admire architects’ drawings of vertical farms or get local authority procurement officers to tick the right ‘sustainable’ boxes on supplier contracts.

There are people who grapple with the real challenges in growing enough food for all of us. They work in places like the FAO, the Oxford Martin School, DEFRA and the BBSRC. We based What it takes to feed the city (Part 2 of the Birmingham 2050 Scenarios Report) on the research of the likes of these people, and the UK’s Global Food Security Champion, Professor Tim Benton was kind enough to contribute to it.

Worryingly, though, the research and thinking that characterises these people is seen sometimes as just another perspective, rather than the best evidence we have at the moment, stuff that needs to underpin our decision-making — even if, especially if future research or new technologies challenges today’s science.

So how can we understand the scale of things? Here’s one way:

Calories are (comparatively) easy to grow, easy to manufacture. Yeah, I do realise we require more than calories for a healthy diet, but calories are a useful illustrator for this argument . . .

If each person on average consumes 2K calories per day, then a city of 1M inhabitants such as Birmingham, needs a supply of two billion calories a day. Today, tomorrow and every day thereafter. (We actually consume over 3K per day on average, but that’s another story.)

All of humanity? All 7 billion of us? 14 trillion calories a day. 5110 trillion calories a year. Sustainable Food Cities starts with a numbers game. It’s the sheer scale of the challenge that we need face.